Which of the following pairs of elements are likely to form ionic compounds:

A) helium and oxygen
B) magnesium and chlorine
C) chlorine and bromine
D) potassium and sulfur
E) sodium and potassium
F) nitrogen and oxygen

I believe the answer is d and f

B) Magnesium and Chlorine

E) Sodium and Potassium

To determine which pairs of elements are likely to form ionic compounds, we need to consider their electronegativity values.

Electronegativity is the tendency of an atom to attract electrons towards itself when it is bonded with another atom. Greater electronegativity difference between two atoms indicates a higher likelihood of them forming an ionic compound.

Let's review the given pairs:

A) Helium and oxygen: Both helium and oxygen are nonmetals. Since they both have relatively high electronegativity values, they are more likely to form covalent compounds rather than ionic compounds. So, this pair is unlikely to form an ionic compound.

B) Magnesium and chlorine: Magnesium is a metal and chlorine is a nonmetal. Metals tend to lose electrons, while nonmetals tend to gain electrons. In this case, magnesium has a low electronegativity value compared to chlorine, indicating a significant electronegativity difference. Therefore, magnesium and chlorine are likely to form an ionic compound.

C) Chlorine and bromine: Both chlorine and bromine are nonmetals and have relatively similar electronegativity values. The electronegativity difference between them is not as significant as in the case of a metal and a nonmetal. So, chlorine and bromine are not likely to form an ionic compound.

D) Potassium and sulfur: Potassium is a metal and sulfur is a nonmetal. Similar to the magnesium and chlorine pair, potassium has a low electronegativity value compared to sulfur. Thus, potassium and sulfur are likely to form an ionic compound.

E) Sodium and potassium: Both sodium and potassium are metals. Metals do not tend to form ionic compounds with each other; instead, they typically form metallic compounds or alloys. So, sodium and potassium are unlikely to form an ionic compound.

F) Nitrogen and oxygen: Both nitrogen and oxygen are nonmetals. They have similar electronegativity values. Therefore, the electronegativity difference is not significant, making them more likely to form covalent compounds rather than ionic compounds.

Based on the explanation above, the pairs that are likely to form ionic compounds are:

B) Magnesium and chlorine
D) Potassium and sulfur

You are correct. The elements potassium (K) and sulfur (S) tend to form an ionic compound because potassium readily loses one electron to achieve a stable electron configuration, while sulfur tends to gain two electrons to achieve a stable electron configuration. Similarly, nitrogen (N) and oxygen (O) can also form an ionic compound since nitrogen typically gains three electrons and oxygen typically gains two electrons to achieve a stable electron configuration. Therefore, the correct pairs of elements likely to form ionic compounds are D) potassium and sulfur and F) nitrogen and oxygen.